People rely on absorbent articles to help participate in and enjoy their daily activities.
Absorbent articles, including adult incontinence articles and diapers, are generally manufactured by combining a substantially liquid-permeable topsheet; a substantially liquid-impermeable backsheet attached to the topsheet; and an absorbent core located between the topsheet and the backsheet. When the article is worn, the liquid-permeable topsheet is positioned next to the body of the wearer. The topsheet allows passage of bodily fluids into the absorbent core. The liquid-impermeable backsheet helps prevent leakage of fluids held in the absorbent core. The absorbent core is designed to have desirable physical properties, e.g. a high absorbent capacity and high absorption rate, so that bodily fluids can be transported from the skin of the wearer into the disposable absorbent article.
The topsheet, backsheet, absorbent core, and other components of an absorbent structure or product may comprise discrete layers or nonlayered shapes and configurations. Furthermore, these components or pieces may be coextensive or non-coextensive, depending on the requirements of the product. Generally each of the individual components or pieces is arranged so that it is in intimate contact along at least a portion of its boundary with at least one other adjacent component or piece of the absorbent article or structure. Typically each component or piece is connected to an adjacent portion of the absorbent structure by a suitable bonding and/or fiber entanglement mechanism, such as ultrasonic or adhesive bonding, or mechanical or hydraulic needling.
Thus, as an absorbent structure or product is made, it generally undergoes a number of different steps in which components or pieces are connected to one another. For example, portions of the topsheet and backsheet typically are bonded together. Also, to the extent the absorbent structure or product incorporates elastomeric regions such as elasticized waistbands or elasticized leg bands or leg cuffs, elastic strands or elastic ribbons are typically bonded to a portion of one or more base materials, substrates, or webs.
If an adhesive is used to attach a portion of one component or piece to a portion of another component or piece to form a composite, the adhesive may be exposed to ultrasonic energy in subsequent processing steps if part or all of the composite passes through ultrasonic-treating equipment. The ultrasonic energy may cause the adhesive to flow. This in turn may lead to build up or accretion of the adhesive on parts of the ultrasonic-treating equipment if the adhesive penetrates through some or all of the composite, between separate layers of the composite if the composite is a laminate, or both. This build up or accretion may decrease performance of the ultrasonic-treating equipment, and may lead to increased down time of the production machine.
What is needed is a composite and absorbent article comprising an adhesive that is less susceptible to building up or accreting on the surfaces of ultrasonic-treating equipment, and a method of making such a composite and article.